1. Field of the Invention
This invention relates to a reinforcing tape or reinforcing sheet material to be attached to the end portion of a fastener tape which is intended for allowing attachment of a pin-and-socket separator.
2. Description of the Prior Art
The reinforcing tapes to be attached to the end portions of fastener tapes have been heretofore known in various types. The conventional reinforcing tapes include those which, for the sake of obviating the necessity of preparing reinforcing tapes dyed specially in various colors matched to the colors of dyed fastener tapes and consequently saving such time and labor as would otherwise be incurred in the inventory control, use transparent synthetic resin films in a superposed manner so as to show the colors of the dyed fastener tapes therethrough. For example, the reinforcing piece which is formed of two superposed transparent synthetic resin films having different melting points and is adapted to be applied fast to a fastener tape by melting that of the two films having a lower melting point as disclosed in Japanese Utility Model Publication No. (hereinafter referred to briefly as xe2x80x9cJUM-B-xe2x80x9d) 44-25,843 and the lateral application tape which is formed by superposing on one side of a transparent film of nylon 6 or nylon 66 a transparent polyester copolymer film having a melting point of not more than 200xc2x0 C. so as to show the color of the base fabric of the fastener tape therethrough as disclosed in published Japanese Patent Application, KOKAI (Early Publication) No. (hereinafter referred to briefly as xe2x80x9cJP-A-xe2x80x9d) 62-149,780 have been known to the art.
Since the reinforcing tapes formed of two layers of synthetic resin film as are disclosed in JUM-B-44-25,843 and JP-A-62-149,780 mentioned above are hard from the material point of view, they cannot be easily shaped by bending in conformity with the shape of the core portion of the fastener tape intended for permitting attachment of a pin-and-socket separator and, for this reason, the core portion of the fastener tape is not easily formed accurately in contour thereof. Further, these reinforcing tapes have the problem that when they are repeatedly bent, the bent lines thereof ultimately cause whitening possibly to the extent of jeopardizing the appearance of the reinforcing tapes.
To solve such problems, JP-A-8-299,033 and JP-A-10-306,262 filed by the assignee of this application propose reinforcing tapes using a transparent polyester elastomer film as a surface layer and having an adhesive layer superposed on the reverse side thereof.
The reinforcing tapes disclosed in JP-A-8-299,033 and JP-A-10-306,262 mentioned above have the surface layer (reinforcing layer) thereof formed of a polyester elastomer film and, therefore, enjoy the advantage of possessing flexibility enough to be folded in conformity with the contour of the core portion of the fastener tape as compared with the aforementioned reinforcing tape formed of synthetic resin film.
When the elastomer film is used for the reinforcing layer and this film happens to be supple, excellent in transparency and soft, however, it is at a disadvantage that the reinforcing tape will be easily stained by a dry cleaning liquid when it is somewhat muddy. Further, since the film is deficient in resistance to washing and resistance to dry cleaning, the goods having fastener tapes attached thereto, on being washed or dry cleaned, encounter the problem that the reinforcing tape readily swells and the peel strength between the reinforcing tape and the fastener tape is degraded to the extent of rendering the reinforcing tape easy to peel. Moreover, the slide fastener using a polyester elastomer film is somewhat inferior to that using a polyamide elastomer film in their strength, uniformity of color with the fastener tape, flexing resistance, cold temperature resistance, and light-fastness.
It is, therefore, an object of the present invention to provide a reinforcing tape for a slide fastener, which excels in stain resistance to a dry cleaning liquid and exhibits high peel strength between the reinforcing tape and the fastener tape, while maintaining advantages of the elastomer film as the reinforcing layer of possessing suppleness and excellent transparency.
Another object of the present invention is to provide a reinforcing tape for a slide fastener, which possesses good resistance to washing and to dry cleaning and stain resistance in combination with high strength, flexing resistance, cold temperature resistance, and light-fastness.
To accomplish the objects mentioned above, the present invention provides a reinforcing tape for a slide fastener, which tape is characterized by comprising in combination a polyamide elastomer film manifesting a modulus of elasticity in bending in the range of 6,000 to 9,000 kg/cm2 and an adhesive layer.
In a preferred embodiment of the present invention, a polyester-based hot-melt adhesive is used for the adhesive layer.
In another preferred embodiment of the present invention, an intermediate layer is interposed between the polyamide elastomer film and the adhesive layer, wherein the intermediate layer has a thickness thinner than the thickness of the elastomer film and that of the adhesive layer. In this case, a polyester-based anchor coat agent is advantageously used for the intermediate layer.
Since the reinforcing tape of the present invention uses as a reinforcing layer the polyamide elastomer film manifesting a modulus of elasticity in bending in the range of 6,000 to 9,000 kg/cm2 as mentioned above, it excels in stain resistance to a dry cleaning liquid and possesses good resistance to washing and to dry cleaning and stain resistance in combination with high strength, flexing resistance, cold temperature resistance, and light-fastness, while maintaining advantages of the elastomer film as the reinforcing layer of possessing suppleness and excellent transparency. Further, by interposing a relatively very thin intermediate layer between the polyamide elastomer film and the adhesive layer to improve the interlaminar strength thereof, it is possible to increase the peel strength between the reinforcing tape and the fastener tape and improve the resistance to washing and to dry cleaning and the stain resistance. By bonding the reinforcing tape of the construction described above to the end portion of a fastener tape through the medium of the adhesive layer, particularly a polyester hot-melt adhesive layer, the fastener tape is enabled to acquire a reinforced part having the reinforcing tape joined thereto with thorough adhesive strength. Further, since the reinforcing tape of the present invention is transparent or translucent and excels in flexibility, it can be easily shaped in perfect conformity with the contour of the core portion of the fastener tape. When it is repeatedly folded, the folded portion is not whitened. Furthermore, when it is fixed to the fastener tape, it allows the color of the fastener tape to be directly seen therethrough and will not impair the appearance of the fastener tape.